Boron tribromide → (S)-5-amino-2'-bromo-4'-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9'-xanthen]-7'-ol

Participants

Reaction Conditions

Reaction Steps

In a 500-mL flask, the (S)-2′-bromo-4′-fluoro-7′-methoxy-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-5-amine (0.595 g, 1.513 mmol) was dissolved in DCM (45 mL). The orange solution was cooled to 0° C. and a DCM solution of boron tribromide (1.0 M, 4.54 mL, 4.54 mmol) was added. After 2 h, the reaction mixture was quenched with 20 mL of 9:1 NH4Cl/NH4OH. The mixture was diluted further with water (10 mL) and the aqueous phase was extracted with 5% MeOH-dcm (3×60 mL). The organics were combined, washed with brine (20 mL), dried over sodium sulfate and concentrated to afford crude (S)-5-amino-2′-bromo-4′-fluoro-2,6-dihydrospiro[[1,4]oxazine-3,9′-xanthen]-7′-ol (0.574 g, 1.21 mmol) which was used directly in the next step.

Provenance & Evidence